require 'digest/sha1'
module AuthenticatedBase
  # Virtual attribute for the unencrypted password
  attr_accessor :password

  def self.included(base)
      base.validates_presence_of     :email
      base.validates_presence_of     :password,                   :if => :password_required?
      base.validates_presence_of     :password_confirmation,      :if => :password_required?
      base.validates_length_of       :password, :within => 4..40, :if => :password_required?
      base.validates_confirmation_of :password,                   :if => :password_required?
      base.validates_length_of       :email,    :within => 3..100
      base.validates_uniqueness_of   :email, :case_sensitive => false
      base.before_save :encrypt_password

      base.extend ClassMethods
  end
  
  # Authenticates a user by their email and unencrypted password.  Returns the user or nil.
  module ClassMethods
    def authenticate(email, password)
      u = find_by_email(email) # need to get the salt
      u && u.authenticated?(password) ? u : nil
    end

    # Encrypts some data with the salt.
    def encrypt(password, salt)
      Digest::SHA1.hexdigest("--#{salt}--#{password}--")
    end
  end

  # Encrypts the password with the user salt
  def encrypt(password)
    self.class.encrypt(password, salt)
  end

  def authenticated?(password)
    crypted_password == encrypt(password)
  end

  def remember_token?
    remember_token_expires_at && Time.now.utc < remember_token_expires_at 
  end

  # These create and unset the fields required for remembering users between browser closes
  def remember_me
    remember_me_for 2.weeks
  end

  def remember_me_for(time)
    remember_me_until time.from_now.utc
  end

  def remember_me_until(time)
    self.remember_token_expires_at = time
    self.remember_token            = encrypt("#{email}--#{remember_token_expires_at}")
    save(false)
  end

  def forget_me
    self.remember_token_expires_at = nil
    self.remember_token            = nil
    save(false)
  end

  protected
    # before filter 
    def encrypt_password
      return if password.blank?
      self.salt = Digest::SHA1.hexdigest("--#{Time.now.to_s}--#{email}--") if new_record?
      self.crypted_password = encrypt(password)
    end
      
    def password_required?
      crypted_password.blank? || !password.blank?
    end
  end
